In our endeavor to identify new, less-toxic therapies for prevention and treatment of human prostate cancer, we propose to study a dietary agent resveratrol, a polyphenolic compound found in grapes and wine. Resveratrol exerts striking inhibitory effects on diverse cellular events associated with tumor initiation, promotion and progression, thus holds great promise for development as a chemopreventive agent for prostate cancer. Furthermore, resveratrol sensitizes prostate cancer cells to TRAIL (TNF-related apoptosis-inducing ligand), which is a biologically important cytokine. Besides these advances, the intracellular mechanisms by which resveratrol inhibits proliferation and induces apoptosis in tumor cells are not fully defined. Overall rationale for the evaluation of efficacy of resveratrol against prostate cancer comes from epidemiological data and from our preliminary studies. We hypothesize that resveratrol will be highly effective in suppressing growth of human prostate cancer cells, due to its ability to (a) induce apoptosis through upregulation of death receptors and proapoptotic members of the Bcl-2 family and activation of caspases, and (b) activate FOXO family of transcription factors. The specific aims of the project are: (1) To determine the intracellular mechanisms by which resveratrol inhibits proliferation and induces apoptosis in human prostate cancer cells; and to determine the molecular mechanisms by which resveratrol sensitizes prostate cancer cells to TRAIL; (2) To examine the mechanisms by which FOXO family of transcription factors regulate the Bcl-2 family members, cell cycle regulatory genes and apoptosis in prostate cancer cells treated with resveratrol; and (3) To determine the effect of resveratrol and TRAIL on growth of human prostate cancer xenografts in vivo in nude mice, and to determine the mechanism of resveratrol and TRAIL-mediated in vivo growth inhibition of prostate cancer xenografts. Specifically, studies are designed to determine the contribution of mitochondrial and/or death receptor pathways, and PI3-K/Akt/FOXO activity in resveratrol-induced apoptosis. The down-stream apoptosis-related targets of FOXO transcription factors will be identified. The interactive effects of the resveratrol and TRAIL will be assessed in terms of xenograft growth and tumor regression. Thus, resveratrol based strategies can be utilized for prevention and treatment of prostate cancer, and in the long-term it may have profound impact on the overall incidence of human prostate cancer.